Improved furnace foe heating articles of steel ii the process of tempering



B. S. STOKES. Tempering SteeL` hv vf/v rok. www@ rLFETERS, PHoTo-LlTHOGRAPHER, wAsHxNGToN n C @with tetta -ettat titte.

BENJAMIN S. STOKES, OE MANCHESTER, NEW HAMPSHIRE.

Letters Patent No. 65,516, dated June d, 1867.

IMPROVED' IURNAGE FOB HEATING ARTICLES OF STEEL IN THE PROCESS 0l?l TEMPERING.

'cla stigma Infant tn' ni iluso Eaters geteilt mit mating putt nt the 5min.

TO ALL WI-IOM IT MAY CONCERN: y

Be it known that I, BENJAMIN S. STOKES, ofManchestcr, in the county of Hillsboro, and State of New Hampshire, have invented certain improvements in Furnaces for Heating Articles of Steel in the Process of Tempering, of which the following is a full, clear, and exact description, reference being ha-d to the accompanyi'ng drawings, Kmaking part of this speciiication, in which- Figure 1 is a perspective view of a furnace with my improvements applied thereto.

Figure 2 is a longitudinal vertical section; and l Figure 3 is a transverse vertical section through the same. l

Figure 4 is a perspective view of the muilc or receptacle for the reception of the articles while being heated. v

In the method of tempering tiles, and various kinds of cutlery and edge tools, such as knives, plane-irons, dto., it is customary to immerse the article within a metallic bath, the temperature of which corresponds to that required for the article to be tempered. The action of the intense heat on the crucible containing the metallic bath is either liable to destroy the crucble or render the iron of which it is made so porous as to aildw the leadof which the bath is composed to leak through and be lost in the fire. The crucible has also been placed within a jacket, and a space left between them for the reception of sand to prevent the Crucible from being oxidized by contact with the ire. This method answered a better purpose than that above mentioned, but the jacket was expensive, and a liability still existed of a portion of the lead being wasted.

To overcome the above-mentioned difficulties is the object of my invention, which consists in a cellular muiiie or receptacle, into which are placed the articles to be heated, the heat being allowed to circulate freely entirely around the ,muflef which, although rendered porous by the expansion and contraction resulting from diiferent temperatures, still retains its form, and is more durable than the crucible, while at the same time the expense and inconvenience of using the metallic bath are avoided.

vMy invention also consists in placing the due in a position not far` from and above the door, in order that the heat may be concentrated at' this point to counteract the effect produced by the entrance of the cold air from without when the furnace door is opened for removing articles from and placing others within the mufile, which would otherwise in a measure cool those already therein and prevent them from being properly tempered.

My invention also consists in constructing the door of the furnace with a double casing, forming an airspace, whereby the operator is not affected by the direct radiation of the heat which Would'otherwse occur.

To enablel others skilled in the art to understand and usc my invention, I will proceed to describe the 'manner in which I have carried it out.

In the said drawings, A represents the Walls of the turnace, B the top, and C the ue, which is commanded by a damper, a. Within the furnace is formed a bed, D, of fire-brick, or other suitable material, the upper surface of which is on a level, or nearly so, with the bottom of the opening E, which is closed by the door F,

which slides vertically in guides a', and has attached to its upper end a chain, b, which runs over pulleys and carries a weight, cl, by which the door is balanced and held open at the required height. On eachside of the bed D is placed 'a furnace, Gr, (iig. 3,) which is supplied with fuel through the door H, and beneath each furnace is an ash-pit, I, provided with` e door, J. I( is a cellular maille or receptacle, formed of Afire-brick, cast iron, or other suitable material, (seen detached in iig. 4,) in which are placed the articles to be heated, themufde being raised a little above the surface of the bed D by means of transverse projections e on its under side, so as to allow the fiame and heat from the furnaces to circulate freely around it. The articles to be heated, previous to being placed in the cellsf of the inutile K, are coated with a suitable mixture of iiour or meal, ground anthracite coal, and salt, to protect them from oxidizaton and scaling. The tine C is placed at the front end of the furnace and almost immediately over the opening E, so as to counteract the effect produced by the entrance of cold air when the door F is opened for the purpose of removing articles from and placing others within the mutlie K, which would otherwise cool those already in the cells f. The door F is made double, with an air-space, g, so as to protect the operator from the direct radiation of heat which wouldvotherwise occur. An opening may be formed in the top B of the furnace instead of at E, and the mufiie" inserted in a vertical position, its upper end being exposed to the nir, and forming a, portieri of the top of the furnace; or n 'furnace may be constructed Vin which the mulie cnn be inserted in a. horizontal position and form a portion of the top of the furnace, its cells or receptacles being left open at the top for convenience of inserting or withdrawing the articles to be heated, which will be found to unswera. good purpose when only the lower portion of' the nrticle requires to be heated.

What I claim as my invention, and desire to secure by Letters Patent, is@ The cellular ,muHe K, substantially als and for the purpose set forth.

I also claim pla-cingthe ue C at or near the front of the furnace, forthc purpose described. I also claim forming an air-space, g, within the door F, substantially as and for the purpose set forth. I also claim the cellular muille K, in combination with a. furnace provided with a Hue, C, .und :L double door, F, constructed und operating substantially as described.

BENJAMIN S. STOKES.

VWitnesses:

N. W. STEAnNs, P. E. TEscnEMAcIHER. 

